When attaching items to the human body, such as prosthetic orthotic appliances, it is desirable to have an accurate fit to optimize results and reduce discomfort. The same holds true for shoes, gloves and other sports-related items.
FIG. 1 is a drawing that shows a typical orthopedic brace designed for the knee. The device, shown generally at 100, includes an upper portion 102 secured to the area above the knee joint 108, and a lower portion 104 secured below the knee. To control appropriate range of motion, hinges 103, 106 are provided on the lateral and medial sides, and these hinges connect to stiff bars 110, 112, which are secured with Velcro® straps 120, 122, which are tightened around the leg. The hinges 103, 106 may include gages and guides to increase and decrease range of motion, depending upon the condition of the wearer.
Apart from the appliance of FIG. 1 being heavy, bulky, and generally expensive, the general concept of securing devices of this kind to the leg or other appendage utilizing straps simply does not work. Due to the weight and location of the device, during walking in particular, it slips down, causing the axes of the hinges 103, 106 to fall, thereby effectively defeating the overall effectiveness of the product. In addition, the bulk of the unit tends to cause the wearer to don the appliance over one's clothing, exacerbating the problem with loosening and misalignment.
Particularly with respect to prosthetic devices such as artificial limbs, it has been recognized that suction may be advantageously used to hold the appliance in position. As discussed in U.S. Pat. No. 5,376,131, artificial limbs using suction sockets are in widespread use today. These sockets are provided with a one-way air valve so that, on placing the stump of the patient's leg into the socket, the air is expelled from the interior of the socket to the outside, thus creating a partial vacuum in the airspace between the patient's stump and the interior of the socket. The difference in pressure between the atmospheric air outside the socket and the vacuum within the socket holds the socket in place until air is readmitted to the socket by opening the one-way valve.
A major pitfall of the suction socket is the inability to provide an effective seal at the proximal open end of the socket. Even if the socket is perfectly fitted to the patient's stump, the stump will contract or shrink during the course of the day, thereby permitting air to leak into the socket, thereby reducing and in some cases completely eliminating the differential air pressure between the atmospheric air outside the socket and the airspace between the patient's stump and the socket. A variety of techniques have been adopted to address this problem, such as providing the patient with special socks to accommodate for this shrinkage. However, in practice, the patient must remove the prosthesis to apply the sock as suction is lost during the day, which is certainly inconvenient.
Another attempt to address this problem is the provision of auxiliary suspension devices, such as belts or the like, to hold the socket in place during the course of the day. This simply adds to the weight and bulk of the prosthesis and does not address the cause of the problem, namely the loss of suction due to shrinkage of the patient's stump.
The invention of the '131 patent solves this problem through the provision of a self-adjusting sealing member adjacent the proximal open end of the suction socket adapted to maintain the seal between the proximal open end of the socket and the patient's stump as the stump shrinks during the course of the day.
Inflation, as opposed to suction, has for years been used to improve the fit of athletic shoes such as running shoes. To reference one patent of many, U.S. Pat. No. 5,253,435 teaches a bladder assembly for an athletic shoe and having at least first and second chambers. The chambers are independently and separately pressure adjustable by the user to conform to different concavity areas of his foot, such as the arch, ankle and metatarsal areas, to thereby enhance fit, comfort and athletic performance. Both chambers are inflatable by the same articulated on-board pump and deflatable by the same on-board depressible plunger. A dial on the lateral side of the upper allows the user to select which of the chambers is to be pressure adjusted, that is, which of the chambers is in pressure communication with the pump and the plunger. When the dial is in a neutral position, accidental inflation or deflation of either chamber is prevented.
Active evacuation has been used with respect to materials that make skin contact, but only for the purpose of waterproofing. U.S. Pat. No. 4,768,501, for example, comprises a method of waterproof sealing a patient's cast or dressing through the use of a water- and air-impervious flexible membrane. The method includes the steps of placing the membrane over the cast or dressing so that the membrane's edge margin extends over a portion of the patient's skin along a perimeter of the cast or dressing. In the next step a vacuum is formed between the membrane and cast or dressing sufficient to cause atmospheric pressure to force the membrane into sealing contact with the skin and with a snug, close fit with the cast or dressing. In one embodiment the vacuum is formed by inserting a suction tube through the interface between the membrane edge margin and skin and evacuating air through the tube. After the sealing contact between the membrane and skin is formed the suction tube is withdrawn. In another embodiment the vacuum is formed by evacuating air through an air valve which is provided in the membrane.
In view of these teachings, the need remains for improved articles and methods for securing prosthetic, orthotic, and sports-related equipment to the human body.